This invention relates to a plug part for an optical plug-and-socket connection.
In contrast to electrical plug-and socket connections, with optical plug-and-socket connections the exact fitting position of the plug pin plays an important role in the quality of the transmission performance. The lock element thus has the job of locking the plug part in the socket part in a pull-proof manner. The locking is effected, as a rule, automatically on reaching the final insert position. When pulling out the plug part a manual unlocking movement must be carried out.
With comparable plug parts, the locking element as a rule is formed as one piece with the plug housing. It has the shape of a lever which via a bending link is resiliently connected to the housing and on whose end detent pawls or other locking elements are arranged. One example for such a plug part is shown and described in international publication WO 98/53347. One disadvantage of this design, however, lies in the fact that the plug housing must be manufactured as a complicated injection molded part. The bending link may become weaker with time so that the locking element may no longer carry out is function. Furthermore, a plastic material with suitable bending properties is not necessarily well suited for the plug housing.
There are already known other plug parts with which locking elements may be applied as separate components. Thus U.S. Pat. No. 4,759,599 shows an optical plug which, for locking with a socket part, is provided with a locking mechanism which opens in a jaw-like manner and which is spring-biased. This mechanism consists of a lever pair which is pivotably mounted on axes, wherein a torsion spring engages on each lever. This construction type is relatively complicated and for unlocking the plug part both individual levers must be uniformly actuated. With a high packing density of the plug, this for reasons of space is no longer possible. Similar locking mechanisms with mutually opening lever pairs are disclosed also in U.S. Pat. No. 4,737,008 and in U.S. Pat. No. 5,154,629.
It is therefore the object of the invention to provide a plug part of the initially mentioned type which is provided with a locking element that is easy to manufacture and which functions well. The locking element should furthermore also be able to be well operated and the handling of the plug part should not be inhibited by projecting parts and the like. These objects are achieved according to the invention with a plug part as described below.
The locking element, fastened to a rotational link pivotably on the plug part, is resiliently supported on the plug housing. A resilient connection per se via a bending link is therefore not necessary. The locking element may in this manner be formed as a one-piece bent part of metal. Even after numerous actuations appearances of wear do not occur.
Advantageously, the locking element is snapped onto the plug housing by which means the assembly or the replacement of a locking element may be considerably simplified. A particularly advantageous snap connection is achieved by way of the fact that the plug housing comprises a pair of link cams and that the locking element comprises a pair of corresponding recesses into which the link cams engage. Conceivably, it could also be fastened by way of a separate pivot or the like.
One advantageous resiliency system of the locking element may be achieved when it comprises a leaf spring whose one end rests on the plug housing in such a manner that the leaf spring biases the locking element into a locking position. The locking element is advantageously design such that it comprises two roughly parallel arms and a grip piece which connects the arms and on which the leaf spring is arranged. The two arms are arranged laterally from the plug housing.
The leaf spring may be easily integrated on the bent part of metal and such bent parts may be easily manufactured in large numbers. On the free ends of the arms detent pawls in the form of bends may be arranged. The detent pawls run at an acute angle to the longitudinal middle axis of the plug part an in this manner form ramps on which the arms are pivotable against a spring force on insertion into a socket part.
In certain cases it is also useful for reasons of space when the arms on pivoting the locking element against the spring bias at least partly sink into corresponding recesses in the plug housing.
The locking element is advantageously linked onto the cable-side end of the plug part. In this manner it may be easily actuated with the thumbs on the grip piece. A linking onto the plug end-face side of the plug part would, however, also be conceivable.
An optical plug-and-socket connection is with the help of the described plug part manufactured together with a socket part which comprises at least one socket for receiving the plug pin, wherein the locking element on reaching the final insertion position engages into at least one undercut on the socket part. Thus without further ado it is possible for the plug part according to the invention to be combined with a conventional socket part.
A particular advantage may be achieved when the socket part comprises a surface section which lies over the insert opening and which, with a surface section on the locking element, encloses an obtuse angle, whereby the surface sections connect to one another essentially continuously. With the surface section on the locking element, this is so preferably for the grip piece. With this arrangement, no sort of hook-like projections arise on which the relatively thin fiber-optic cable may get snagged.
The socket part is particularly advantageously composed of two equal housing halves which between themselves accommodate the actual socket. On such a socket part the undercuts required for the locking element may also be manufactured particularly simply with regard to molding technology.
Further advantages result when at least one insert opening of the socket part is provided with a pivotable protective flap which is linked on by way of a pivot passing through the socket housing and the protective flap. As with the plug part, the protective flap also on the socket part prevents the exiting of laser light. The linking by way of a pivot is also possible with difficult space conditions and ensures a secure connection between the protective flap and the housing. The protective flap may thus be biased by way of a spring which is seated on the pivot. The spring is advantageously a helical torsion spring.
A particularly simple securement with respect to the relative position between the protective flap, spring and pivot may be achieved when the pivot comprises a circumferential groove and when the protective flap is provided with a spur which for the lateral fixation of the pivot engages into the groove.
Also the protective flap may advantageously be designed as a bent metal part.
On the socket part on both sides of the insert opening two undercuts for the locking element in the form of cams may be arranged, wherein the protective flap with a removed plug part bears on the cams. The cams fulfil in this manner a double function as limiting elements for the protective flap being under spring bias and as a counter bearing for the locking element.
Individual previously mentioned features on the socket part may also be realized in combination with conventional plug parts. This in particular concerns the two part housing design and/or the design of the protective flaps.